The present invention relates to a rotary sander and more particularly to a rotary sander having a structure which facilitates rapid disassembly and assembly for the replacement of the elements therein.
Referring to FIG. 1, a conventional type of rotary sander comprises a circular top cover 1 and bottom cover 2, a retaining sleeve 3 disposed therebetween, and a set of sanding units 4 secured to the sleeve and a set of brushes 5 retained by the covers.
The lower end portion of sleeve 3 is enscounced in a stepped diameter central hole 21 in the bottom cover while the upper coupling portion 31 thereof with a reduced diameter passes through a central hole 11 in the top cover. A circular partition plate 6 having a central hole is further provided and disposed between the shoulder of coupling portion 31 and the top cover, with a set of downwardly aligned protrusions 12 formed around hole 11 engaging corresponding apertures 61 formed around the central hole of the partition plate.
Sandpaper sheets 41 of each sanding unit 4 are first secured to the outer periphery of the retaining sleeve prior to assemblage with the covers.
To effect the securement, a corresponding edge portion of each sandpaper sheet is clamped to the periphery of sleeve 3 by an elongate clamping plate 42 whose ends are fastened to corresponding threaded holes 32 thereon with respective screws 421.
Radial and annular dividers in the peripheral portions of bottom cover 2 and partition plate 6, along with a circumferential rim 13 of the top cover 1, define respective sets of receiving recesses, 22 and 62, thereon for the positioning of the brushes.
Each brush 5 has an elongate spine 51 whose end portions are received within respective recesses, 22 and 62, on cover 2 and partition 6. A sandpaper sheet 41 extends through a gap defined between each pair of adjacent brushes 5 as shown in FIG. 4. An annular bonnet 7 having a set of downwardly aligned protrusions 71 is positioned over the protruding terminal end of the coupling portion 31 with the protrusions engaging corresponding radial slots 311 thereon.
At least two ribbons 8 are passed through the central bore of the assembly, defined by the central holes of the bonnet, top and bottom covers, and partition, and the hollow core of the retaining sleeve. The ribbons are wrapped axially over the drum and knottedly adjoined to secure the assembly together.
A major deficiency of this type of conventional rotary sander is that disassembly for the replacement of worn sandpaper or the cleaning of the brushes tends to be cumbersome and time consuming. In particular, after the ribbons 8 are first unknotted and the top cover removed, the removal and subsequent replacement of sandpaper sheets 41 requires the manipulation of a plurality of screws. Furthermore, it is not uncommon for the dust laden brushes to come free from bottom cover 2 upon the removal of the sleeve 3 and sanding units 4, adding to the number of manipulations required to complete the procedure.
The rotary sander of the present invention overcomes this shortcoming by providing a sliding securement between the sanding units and retaining sleeve thereof, as well as for the attachment of the brushes to the rotary drum. Along with other modifications this feature greatly facilitates the rapid and efficient disassembly of the rotary sander.